Muller

ABSTRACT

A muller for finely mulling a material to be processed is disclosed. The muller comprises a nozzle unit ( 10 ) including feed lines ( 12   a  and  12   b ) and hollow pipe lines ( 120   a  and  120   b ), a mulling unit ( 20 ) including a mulling head ( 22 ), and an input device ( 30 ) including a hopper ( 310 ) and a feeder ( 322 ). The muller finely mulls the material even if it has a relatively large particle size, and continuously feeds the material while mulling it in order to improve productivity. The muller conducts cold mulling of the material or maintains the temperature thereof by employing a cooling system to prevent the generation of heat due to inter-material collision as the material is transferred, or friction against the feed lines, thereby extending the lifespan of the muller. The muller requires no separate classifier by employing successively arranged mulling units ( 20   a  to  20   n ) to accomplish a high economical efficiency.

TECHNICAL FIELD

The present invention relates to a muller, and more particularly to amuller for mixing a material to be processed in an air of high pressureand very low temperature, transferring the material mixed in the air,injecting the material using a nozzle at a very high pressure, andcolliding the material against a mulling head, thereby finely mullingthe material.

BACKGROUND ART

A mulling process is an easy process for manufacturing powder. Variousmulling processes have been developed since ancient times. Powdermanufacturing in the chemical industry, mining industry, and so on, hasthe purpose of enhancing a subsequent process efficiency using a largespecific surface area of powder, mixing it with another material, orseparating and recovering a useful component in a rock, rather than thepurpose of obtaining powder itself. The mulling process is also appliedto a living body.

Notwithstanding a long history, a mulling process has characteristics ofa unit operation in that it requires consumption of a great amount ofenergy, and efficiency thereof is considerably low. Further, researchinto mulling has been considerably delayed compared to other researchfields. Meanwhile, since a particle diameter distribution considerablyaffects development of new materials, a mulling process for achieving adesired grain distribution will become more important in the future.

As generally known, a solid body has cohesion energy. If the solid bodyis mulled and then a new surface is generated, the cohesion energy isconverted to surface energy.

If the newly generated surface area is increased as mulling progresses,the surface energy is also increased. Then, if both become equal, themulling process no longer progresses, thereby reaching the mullinglimit.

Change of various physical properties due to such a mulling process isutilized in several fields.

That is, there are advantages, such as surface area increase, reactivityimprovement, density increase, thermal capacity decrease, resolutionimprovement, viscosity change, adhesion force increase, reaction rateimprovement, thinning, and so on, in chemistry and metal fields.

Further, there are advantages, such as transparency increase, glossimprovement, smoothness improvement, dry velocity improvement, freshnessimprovement, osmosis into fiber, and so on, in the pigment and cosmeticsfields.

Further, there are advantages, such as surface area increase, treatmentfor being fit to drink, precipitation decrease, mixability improvement,uniformity of particle diameter, absorptiveness improvement, osmosisimprovement, and so on, in the food and medicine fields.

According to usages of ultra fine particles having these advantages,they are variously used in new material fields such as ceramics,superconductors, and so on, the chemical field for petrochemicals,pigments, paint, resins, toner, and so on, the medicine field forcosmetics, injectable solutions, sugars, proteins, and so on, and thefood field for calcium, vitamins, enzymes, food additives, and so on.

Various mullers have been developed due to the above stated advantagesof the usages of the ultra fine particles.

Such a mulling process is a unit operation for obtaining fine particlesby finely mulling solid material via mechanical methods. That is, themulling process is one of the ancient unit operations in flour milling,pigment manufacturing, ore processing, and so on. Various kinds ofmullers are known, and improvement of the muller has long been required.

Mullers may be generally classified according to particle size (mainly,product particle). That is, according to particle size, mulling may bebroadly classified into crushing (several tens of an to between 10 and19 cm), intermediate crushing (several cm to several tens of m m),comminuting (several cm to between 10 and 19 m m), and fine comminuting(several mm to several m m). Further, mullers may be classified by apower transmission mechanism (for example, reciprocating, rotary, link,and so on), and an actuating system (for example, compression,vibration, and so on).

Compression Type

A jaw crusher crushes a rock positioned between a fixed disc and amovable disc using a strong compression force. The crushingcharacteristics are different depending on whether an upper disc is themovable disc (in the input direction of a raw material) or a lower discis the movable disc (in the output direction of a product). The jawcrusher is widely used as a first crusher. A gyratory crusher alsoconducts crushing by compression force. However, the gyratory crusherbites and crushes a rock by eccentrically rotating an inverted innercone. The gyratory crusher requires a small quantity of raw material,having a higher continuity, and easily controls particle size comparedto the jaw crusher. In a cone crusher, the inner cone is noteccentrically rotated. The cone crusher bites and crushes a material byrotation, and obtains a finer particle size.

High Velocity Rotation Type

A hammer crusher crushes a raw material by cutting, shearing, andcollision by rotating a cutter or a hammer at a high velocity. Hammercrushers are widely used. The hammer crusher covers a considerably smallmulling area by repeating a collision repulsion using a repulsion platemounted to an inner wall of the crusher. Further, the hammer crusherconducts some classification by mounting a screen or a grid at a lowerpart of the crusher.

Among known crushers, there are jaw crushers, cone crushers, hammercrushers, cutter mills, shredders, hammer mills, roll crushers, edgerrunners, stamp mills, disc mills, pin mills, and so on.

Further, mulled material to be processed is recovered through particlesize classification based on particle characteristics and particlediameter. Among known classification methods, there are wind powerclassification and hydraulic classification. Classifiers have also beenvariously devised.

However, according to the prior mullers, there have been problems inthat pulverization is limited, system efficiency is low compared toinput energy for pulverization, and productivity is lower since cleaningof the system is difficult.

Further, there have been defects in that increase of equipment anddecrease of productivity both occur since pulverized material to beprocessed should be separated through a separate classifier.

DISCLOSURE OF INVENTION Technical Problem

Therefore, the present invention has been made in view of the aboveproblems, and it is an object of the present invention to provide amuller for enabling fine mulling of a material to be processed even ifit has a relatively large particle size of several mm.

It is another object of the present invention to provide a muller forcontinuously feeding a material to be processed while mulling it, inorder to improve productivity.

It is another object of the present invention to provide a muller forconducting cold mulling of a material to be processed or maintaining thetemperature of the material by employing a cooling system to prevent thegeneration of heat due to inter-material collision as the material istransferred, or friction against feed lines, thereby extending thelifespan of the muller.

It is yet another object of the present invention to provide a mullerwhich does not require a separate classifier by employing mulling unitshaving the same structure in multiple levels according to fine particlesize requirements in order to accomplish a high economical efficiency.

In accordance with the present invention, the above and other objectscan be accomplished by the provision of a muller comprising a nozzleunit including a feed line and a hollow pipe line for surrounding thefeed line and radially spaced from an outer surface of the feed line,the feed line having one side into which air of high pressure and verylow temperature flows and the other side to which a nozzle is provided,a mulling unit connected to a free end of the nozzle at one sidethereof, the mulling unit including a mulling head spaced from thenozzle on the same axis as the nozzle therein and a downwardly tapered,opened outlet, and an input device connected to the feed line at themiddle of the nozzle unit, the input device including a hopper and afeeder for supplying a material to be processed. The material inputtedfrom the input device is mixed with the air within the feed line andinjected from the nozzle to collide with the mulling head.

DESCRIPTION OF DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a schematic constitutional view showing a muller of thepresent invention;

FIG. 2 is a sectional view showing a primary embodiment of the presentinvention;

FIG. 3 is a sectional view showing a modified embodiment of theinvention shown in FIG. 2;

FIG. 4 is a sectional view showing another embodiment of a material tobe processed input device of the present invention; and

FIG. 5 is a constitutional view showing installation of additionalrecovery devices for recovering mulled material.

BEST MODE

FIG. 1 is a schematic constitutional view showing a muller of thepresent invention.

Referring to FIG. 1, a muller according to the present inventioncomprises a nozzle unit 10 for transferring and injecting a material tobe processed, a mulling unit 20 for finely mulling the material, and aninput device 30 for inputting the material. The nozzle unit 10 includesa feed line and a hollow pipe line for surrounding the feed line andradially spaced from an outer surface of the feed line. The feed linehas one end into which air of high pressure and very low temperatureflows and the other end at which a nozzle 11 is provided. Here,preferably, the air may have a temperature range of −20 to −80° C. Themulling unit 20 is connected to the nozzle at one end thereof. Themulling unit 20 includes a mulling head spaced from the nozzle on thesame axis as the nozzle therein and a downwardly tapered, opened outlet.The input device 30 is connected to the feed line at the middle of thenozzle unit 10. The input device 30 includes a hopper and a feeder forsupplying a material to be processed.

FIG. 2 is a sectional view showing a primary embodiment of the presentinvention. Referring to FIG. 2, the feed line and the hollow pipe lineshown in FIG. 1 include a first line 12 a and a second feed line 12 b,and a first hollow pipe line 120 a and a second hollow pipe line 120 b,respectively.

Specifically, the nozzle unit 10 further includes a first connector 110connected to the first feed line 12 a and the hollow pipe line 120 a,respectively, a second connector 130 for respectively connecting thefirst feed line 12 a and the first hollow pipe line 120 a with thesecond feed line 12 b and the second hollow pipe line 120 b,respectively, and a third connector 140 for connecting the second feedline 12 b and the second hollow pipe line 120 b with the nozzle 11,respectively. Here, the first connector 110 has a flow path forcommunicating with the first feed line 12 a, an inlet 112 for an inflowof the air, and a refrigerant inlet 114, respectively. The flow path ofthe first connector 110 communicates with the air inlet 112 and therefrigerant inlet 114, respectively. The second connector 130 has a flowpath for communicating with the first feed line 12 a and the second feedline 12 b, respectively, and an inlet hole 132 for an inflow of thematerial supplied from the input device 30. The flow path of the secondconnector 130 communicates with the inlet hole 132. The third connector140 has a flow path for communicating with the second feed line 12 b.The flow path of the third connector 140 communicates with a flow pathwithin the nozzle 11. The first connector 110, the second connector 130,the third connector 140, the first feed line 12 a, the second feed line12 b, the first hollow pipe line 120 a, the second hollow pipe line 120b, and the nozzle 11 are arranged as separate elements. Each element ofthe nozzle unit 10 is formed with a flange. Adjacent ones of theelements are connected through the facing flanges, while interposing asealing gasket therebetween.

The first pipe line 120 a and the second pipe line 120 b have portsthrough which cooling nitrogen gas is introduced and discharged,respectively.

Meanwhile, the mulling unit 20 has a T-shaped hollow body, and anL-shaped flow path. The hollow body may be provided with the nozzle 11to connect with the third connector 140. Preferably, the mulling head 22is made of material with a very high hardness. The mulling head 22 facesan injection portion of the nozzle 11. Further, the mulling head 20 hasthe downwardly tapered, opened outlet 24.

The input device 30 loads crushed material to be processed. The inputdevice 30 includes a hopper 310 having a large capacity and formed withan upper cover, and a feeder 320 supplying the material to be processedto one end of an outflow pipe 312 of the hopper to mix the material tobe processed with the air in the feed line.

The feeder 320 includes a feed screw 322, and a feed motor 324 drivingthe feed screw 322.

The input device 30 further includes an inner pressure maintaining pipeline 330. The pipe line 330 equivalently maintains air pressure of thefeed lines and inner pressure within the hopper 310 by connecting anupper part of the hopper 310 with the inlet hole 132.

The operational effects of the primary embodiment of the presentinvention will be given herein below.

Firstly, a material to be processed is crushed to a predeterminedparticle size. After opening the upper cover of the hopper 310, thecrushed material is charged into the hopper 310. Here, the material hasa particle size of about 5 mm or less, allowing it to pass through thenozzle diameter of about 6 mm. Of course, the nozzle diameter may bechanged. Crushing to a particle size of about 5 mm may be economicallyand easily provided by known equipment.

Once the above material to be processed is prepared, the air of highpressure and very low temperature is supplied to the air inlet 112 andthe refrigerant inlet 114. Further, liquid nitrogen may be additionallysupplied to them. Simultaneously, the feed motor 324 is driven to supplythe material dropped by the feed screw 322 to the inlet hole 132 of thesecond connector by the screw feeder.

The supplied material is mixed with the air of high pressure and verylow temperature within the feed line passed through the second connector130, and it is then transferred to the nozzle 11. The material havingpassed through the nozzle 11 is injected at a very high pressure. Then,the material collides against the mulling head 22, and is then finelymulled.

Here, the mulling head 22 is required to be made of a material having avery high hardness. If the mulling head 22 is abraded due to use, it maybe easily exchanged.

Specifically, after releasing the joint portion of the third connector140, the mulling head 22 is removed. Further, the mulling head 22 has ascrew fastening structure for adjusting a distance between the mullinghead 22 and the front end of the nozzle 11.

The finely mulled material is discharged to the outlet 24 tapered andextended to the lower part of the mulling unit 20, and then it isrecovered.

At this time, since a pressure difference is generated between thehopper connected to the feeder communicatively connected to the feedline of the high pressure and very low temperature air and the feedline, it is probable that the movement of the material will be blocked.Thus, the pipe line 330 is connected between the hopper and the feedline to offset the pressure difference and equalize the pressurestherein.

Meanwhile, a temperature increase may be generated within the feed linedue to frictional heat according to the supply of the material to beprocessed and the high pressure air. The temperature increase causes theequipment to be rapidly abraded. Further, the temperature increaselowers the mulling efficiency.

Thus, according to the present invention, a small quantity of liquidnitrogen serving as a refrigerant is supplied through the inlet 114, towhich the high pressure and very low temperature air is supplied, to thefirst connector 110. Then, the liquid nitrogen is vaporized and mixedwith the air. As a result, the temperature increase of the feed line isprevented, and a cold mulling process can be realized. Further, sincedouble cooling is realized by circulating the nitrogen gas within thepipe line 120, dew condensation due to the temperature increase isprevented. As a result, the mulling efficiency is maximized.

Here, it has been determined through experimentation that a straightinjection method has a higher mulling efficiency than a diffusioninjection method.

Next, with reference to FIG. 3, a modified embodiment of the presentinvention will be given herein below.

The modified embodiment provides additional nozzle units and additionalmulling units 20 a to 20 n to the primary embodiment shown in FIG. 2.

Here, the additional nozzle units include feed lines 12 b, hollow pipelines 120 b, and connectors 140 having nozzles with more reduced nozzlediameters.

The mulling units 20 a to 20 n are successively connected in such amanner that one mulling unit is connected to another mulling unitarranged upstream thereof.

According to the modified embodiment, the material firstly mulled by onenozzle is transferred to another mulling unit arranged downstreamthereof by high pressure air, and is then secondly mulled while passingthrough a more reduced nozzle diameter of a nozzle adjacent to anothermulling unit. Thus, when nozzles of nozzle units respectively havinggradually reduced nozzle diameters are successively connected, a finalmaterial discharged through the last nozzle has a considerably smallparticle size.

Next, another embodiment of the input device of the present inventionwill be given herein below.

Referring to FIG. 4, an open type hopper 310 a for successivelyinputting a material to be processed is provided. The hopper 310 a isformed at a lower part thereof with a ball valve 315. The ball valve 314is rotated by a servo motor 316, and upper and lower through holes 317thereof are blocked by a partition 318. An inner pressure maintainingpipe line 330 a is connected between the feeder 320 and a lower part ofthe ball valve 315.

According to the above input device, it is advantageous that a materialto be processed, which is exhausted according to the progress of themulling process, is continuously inputted.

Specifically, according to the hopper of the input device according tothe primary embodiment, since the hopper is closed by the sealed uppercover, it is impossible to continuously input the material to thehopper. However, according to the input device shown in FIG. 4, sincethe upper part of the hopper 310 a is always opened, the material may beconstantly supplemented.

The material received in the upper through hole is rotated downward andsupplied to the feed screw 322, when the ball valve 315 having the upperand lower through holes divided by the partition 318 is rotated by 180°by the intermittently driven servo motor 316. At this time, highpressure within the feed line shuts off reverse inflow of the materialinto the hopper through the partition 318. As a result, the material maybe repeatedly supplied.

Here, if the ball valve is rotated upward by the high pressure airfilled within the lower through hole 318, since the high pressure withinthe hole is rapidly expanded through the lower part of the hopper, thematerial loaded with a high density maintained by the force of gravityand atmospheric pressure, is rapidly dispersed, and the density of thematerial is lowered. As a result, inflow of the material into thethrough hole is smoothly conducted.

Of course, a passage for the material passing through the ball valve isprovided with a pipe line 33 a to maintain the same pressure as theinner pressure of the feed line. As a result, smooth flow of thematerial is secured.

Thus, the present invention provides a muller for preventing the highpressure within the nozzle unit 10 from adversely discharging to theoutside, while improving operation efficiency of the hopper due tocontinuous supply of the material.

A recovery system for recovering the mulled material is shown in FIG. 5.The recovery system includes a plurality of material separators 44.

Specifically, one material separator 44 for conforming a cyclone processis connected to an outlet 24 of the last mulling unit 20 n by a pipeline 42. The separator 44 may be connected to at least one separatoradditionally arranged downstream thereof so as to confirm multistagecyclone processes.

The mulled material passing through the pipe line 42 passes through theseparator 44. At this time, the material is discharged downward due to acentrifugal force, decompression, and reversion. Then, the material issuccessively processed while passing through the next separators. As aresult, the completely mulled material is recovered by separating thematerial from the air.

Meanwhile, in the case of successively connecting the mulling units,circulation of liquid nitrogen may be employed by respectivelyconnecting supply lines of the liquid nitrogen to following nozzlesunits so as to achieve insulation of the mulling unit and the feed linefrom the outside air and cooling of inner heat generated from them.

Further, the feed line transferring the air with the high pressure andvery low temperature may be provided at its inner surface with vortexrifling or inside thereof with a vortex coil to increase mullingpressure due to vortex air generated within the feed line. This vortexgeneration serves to enhance mulling efficiency by increasing injectionvelocity of the nozzle.

INDUSTRIAL APPLICABILITY

As apparent from the above description, the present invention provides amuller for enabling fine mulling of a material to be processed even ifit has a relatively large particle size of several mm. That is, the finemulling is accomplished even if preceding processes such as crushingbefore inputting into the muller are not precisely controlled. Thus,since burden for preceding process of the material is lightened, higheconomical efficiency and high productivity may be expected. Further,the present invention provides a muller for successively feeding amaterial to be processed while finely mulling the material, in order toimprove productivity. Further, the present invention provides a mullerfor enabling cold mulling of a material to be processed or maintainingthe temperature of the material by employing a cooling system to preventthe generation of heat due to inter-material collision as the materialis transferred, or friction of the material against an internal wall ofa feed line, thereby extending the lifespan of the muller. Especially,since cold mulling is progressed according to a property of a materialto be processed, mulling efficiency is increased. Further, the presentinvention provides a muller that does not require a separate classifierby employing mulling units having the same structure in multiple levelsaccording to fine particle size requirements. Thus, equipment expense isconsiderably reduced. Further, since ultra fine mulling and concentratedparticle size nay be secured, practical application of the material andproduct quality may be considerably improved.

Further, the present invention provides a muller which prevents mixingof pre-worked and post-worked material generated upon obtaining mulledmaterial via several devices and processes in the prior art, since themuller of the present invention is able to work the material to adesired particle size finally selected in a single-line by successivelyreducing a nozzle diameter to mull the material to gradually reducedparticle sizes.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

1. A muller comprising: a nozzle unit including a feed line and a hollow pipe line for surrounding the feed line and radially spaced from an outer surface of the feed line, the feed line having one end into which air of high pressure and very low temperature flows and the other end at which a nozzle is provided; a mulling unit connected to the nozzle at one end thereof, the mulling unit including a mulling head spaced from the nozzle on the same axis as the nozzle therein and a downwardly tapered, opened outlet; and an input device connected to the feed line at the middle of the nozzle unit, the input device including a hopper and a feeder for supplying a material to be processed, whereby the material inputted from the input device is mixed with the air within the feed line and injected from the nozzle to collide with the mulling heads, wherein the feed line and the hollow pipe line include a first feed line and a second feed line, and a first hollow pipe line and a second hollow pipe line, respectively, wherein the nozzle unit further includes: a first connector connected to the first feed line and the first hollow pipe line, respectively, the first connector having a flow path for communicating with the first feed line, an inlet for an inflow of the air, and a refrigerant inlet, respectively, the flow path of the first connector communicating with the air inlet and the refrigerant inlet, respectively, a second connector for connecting the first feed line and the first hollow pipe line with the second feed line and the second hollow pipe line, respectively, the second connector having a flow path for communicating with the first feed line and the second feed line, and an inlet hole for an inflow of the material supplied from the input device, respectively, the flow path of the second connector communicating with the inlet hole, and a third connector for connecting the second feed line and the second hollow pipe line with the nozzle, respectively, the third connector having a flow path for communicating with the second feed line, the flow path of the third connector communicating with a flow path within the nozzle, whereby the first connector, the second connector, the third connector, the first feed line, the second feed line, the first hollow pipe line, the second hollow pipe line, and the nozzle are arranged as separate elements, each element of the nozzle unit being formed with a flange, adjacent ones of the elements being connected through the facing flanges, while interposing a sealing gasket therebetween.
 2. The muller as set forth in claim 1, wherein the mulling unit further includes a T-shaped hollow body and an L-shaped flow path, wherein the hollow body is connected with the third connector of the nozzle unit while having the nozzle at one end of the flow path thereof, the mulling head with a very high hardness facing an injection portion of the nozzle.
 3. The muller as set forth in claim 1, wherein the input device loads a crushed material, the input device including the hopper with a high capacity formed with an upper cover and the feeder for supplying the material to an outflow pipe of the hopper to mix the material with the air in the feed line, the feeder including a feed screw and a feed motor for driving the feed screw, the input device further including a pipe line for connecting an upper part of the hopper with an inlet hole of the nozzle unit to equivalently maintain inner pressure within the hopper and air pressure within the feed line.
 4. The muller as set forth in claim 1, wherein the muller further comprises additional nozzle units including feed lines, hollow pipe lines, and connectors connected with nozzles respectively having reduced nozzle diameters, and additional mulling units connected with the additional nozzle units, whereby the additional mulling units are successively connected in such a manner that one mulling unit is connected to another mulling unit arranged upstream thereof
 5. The muller as set forth in claim 4, wherein each of the nozzle diameters is gradually reduced.
 6. The muller as set forth in claim 1, wherein the input device loads a crushed material, the input device including the hopper which is an open type hopper for successively inputting the material, and the feeder for supplying the material to an outflow pipe of the hopper to mix the material with the air in the feed line, the feeder including a feed screw and a feed motor for driving the feed screw, the hopper being provided at a lower part thereof with a ball valve, the ball valve being rotated by a servo motor, the ball valve having upper and lower through holes blocked by a partition, the feeder and the lower portion of the ball valve being connected by a pipe line for maintaining their inner pressures.
 7. The muller as set forth in claim 1 or 4, wherein the muller further comprises a material separator for conforming a cyclone process, the separator being connected to the outlet of the mulling unit by a pipe line, wherein the separator is connected to at least one separator additionally arranged downstream thereof so as to conform multistage cyclone processes.
 8. The muller as set forth in claim 1, wherein the hollow pipe line of the nozzle unit is provided with ports through which refrigerant is introduced and discharged for cooling circulation. 